Reversing mechanism for power engines



June 2, 1936. A. RENNER REVERSING MECHANISM FOR POWER ENGINES Filed Feb.24, 1935 Patented June 2, 1936 UNITED STATES REVERSING MECHANISM FOR.POWER ENGINES Alfred Renner, Berlin-Tegel, Germany, assigner to GeneralElectric Company, a corporation of New York applicati@ February 24,1933, serial No. 658,427 In Germany March 1), 1932 2 Claims.

The present invention relates to reversing mechanisms for power enginessuch as internal combustion engines in which the fuel supply meansincluding pumps and various valves are operated by push rods or the likemoved by means of rotating cams. These cams are fastened to a cam shaftwhich in the case of a combustion engine is usually driven from thecrank shaft.

Reversible internal combustion engines have a cam shaft provided withtwo sets of cams, one set for operating the valve means for onedirection of rotation of the engine and a second set for operating thevalve means in the other direction of rotation. The cams with respect totheir i operationmay be termed forward cams and reversing cams. Thearrangement is usually such that the forward and the reversing cam foroperating a certain push rod are located adjacent each other on the camshaft. For changl ing the direction of rotation of the engine the camshaft or cam holder is moved axially and the push rods are disengagedfrom one set of cams and brought into engagement with the otherr set ofcams. To permit axial movement of the cam shaft or cam holder it isnecessary to move the push rods away from the cams.

One object of the present invention is to provide an improvedconstruction and arrangement of a reversing mechanism for reversibleengines of the type specified.

For a consideration of what I consider to be novel and my invention,attention is directed to the following description and the claimsappended thereto in connection with the accompanying drawing.

In the drawing, Fig. l shows a combustion engine provided with areversing mechanism in accordance with my invention; Fig. 2 shows adetail view of the reversing mechanism to an enlarged scale; Fig. 3 is atop view of a part of Fig. 2; Fig. 4 illustrates a modification of a re-Versing mechanism; and Fig. illustrates a top view of a part of Fig. 4.

The combustion engine shown in Fig. 1 comprises a frame I Il containinga cylinder and a cylinder head II with a valve I2. The valve I2 mayserve for regulating the supply of fuel to the cylinder head Il or thedischarge of burned gases from the cylinder. The valve is moved by afulcrumed lever I3 which has one end pivoted to a push rod I4 carryingat its lower end a roller l5. The roller I5 engages in its operativeposition (see Fig. 2) a cam I5 fastened to a cam shaft or cam holder IIwhich in turn is supported by a bearing I8. During normal operation thecam I6 rotates to force the push rod I4 upward, thereby actuating thevalve I2. The push rod I lI- may be forced downward to maintain itsoperative relation with the cam by means of a spring, (not (Cl. 12S-41)shown), which usually forms a part of the Valve 52.

The arrangement so far described serves for operating the engine in onedirection of rotation. To permit operation in the opposite direction ofrotation, a second cam I9 is fastened to the cam shaft Il and means areprovided for changing the cooperative relation between the cams I6 andI9 and the roller I5. The reversing of the engine, that is, the changeof the cooperative relation between the cams and the roller isaccomplished in accordance with my invention by a mechanism which by thesingle actuation of a certain element removes the roller from theforward cam and brings it into engagement with the reversing cam.

The reversing mechanism shown in Figs. 1 to 3 comprises a link 25 whichis pivoted at 2| to the lower end of the pushrod and at 22 to anotherlink 23. The latter is fastened to a regulating shaft 24 together with alink 25 which in turn is pivoted at 26 to a follower 2l. The follower 2lis pivoted at 28 to a curved disk or positive action cam 29 fastened toa shaft 30. The disk comprises three outer portions (Fig. 3), a planeportion a., a curved portion b and another plane portion c. The bearingI3 is slidably arranged on a support 3l, in the present instance shownas having a dovetail connection 32 with the bearing I8. This dovetailconnection prevents vertical and sidewise movement of the bearing butpermits axial movement thereof. The rim of disk 23 engages two rollers33 and 34 fixed to the bearing. With this arrangement, turning of thedisk 29 causes axial movement of the bearing as soon as the curved outerportion b of the disk or cam is moved between the rollers 33 and 34.Movement of the bearing in turn causes axial movement of the cam shaft,relative movement between the latter and the bearing being preventedbythe provision of rings or collars 35, 3S fastened to the shaft I'I. Apinion 3l (Fig. 1) fastened to the shaft 30 meshes with a rack 38connected to the piston 39 of a hydraulic motor. The latter comprising acylinder 4I) and a pilot valve 4I having a valve member t2 connected toa fulcrumed hand lever 43. The pilot valve has ports iii for supplyingactuating fluid to the cylinder and a port 45 for draining actuatingfluid from the cylinder. In the position indicated in the drawing,actuating fluid is supplied to the left-hand portion of the cylinder anddrained from the right-hand portion thereof, to the effect that the rackis moved to the right and the disk or cam 29 turned in counter-clockwisedirection. If the position of the pilot valve is reversed, a similaroperation takes place but in the opposite direction, resulting inmovement of the disk or cam in clockwise direction. The hydraulicrmotor,together with the pilot valve, represents in substance a reversiblemotor or a power agency for operating the reversing mechanism.

The motion of the links and the follower during the reversing of themechanism comprises two parts or steps. During the first part the rollerI5 is moved away from the cam I6, for example, and during the secondpart the roller l5 is returned and brought into engagement with the camI9. In Fig. 2, I indicates the position of the link mechanism while theroller i 5 engages cam I6, and II the position of the links and thefollower at the end of the above mentioned first part of the motion; themovements have been indicated by arrows. During the second part of themotion the links are moreiy returned from the position II into positionI, whereas the follower 21 assumes a new tion III in accordance with thechanged po on of the cam 29.

In Fig. l I have -own the reversing mechanism in the intermediateposition, that is, at the end of the first part of the reversing motion.

Thus it will readily be seen that turning of the disk 29 causes removingof the roller l5 from the cam shaft thereafterreturning of the roller i5to the cam shaft. While the roller l5 is being moved awa-y from andreturned to the cam shaft, the latter itself is moved or shifted inaxial direction. More specifically, with the arrangement shown in Figs.I, 2 and 3, the axial movement of the cam shaft or cam holder takesplace approximately during the second half of the first part of the linkmotion and during the first half of the second part thereof. No axialmovement of the cam shaft takes place as long as the plane portions oand a are moved between the rollers 33 and Sil of the bearing. Axialmovement of the bearing is caused only while the portion b of the diskis moved between the rollers 33 and Sii. Furthermore, the connectionbetween the follower 2i and the cam 29 is such that turning movement ofthe latter does not effect axial movement of the link mechanism (seeFig. 3). In Figs. 4 and 5, where I have shown a modification inaccordance with my invention, a push rod 56 carries a roller 5i whichengages a cam 52 fastened to a cam shaft or cam holder 53. The latter issupported by a bearing 56 having a slidable support 55. Pivoted to thepush rod is a link mechanism comprising links 56, 51 and 58corresponding to links 28, 23 and 25 respectively in Figs. 1 to 3. Thelinks 51 and 58 are fastened in fixed relation to each other on aregulating shaft 5S. Whereas link 25 in Figs. l to 3 is fastened to afollower 21 moved by a` disk 29, I provide in the arrangement of Figs. 4and 5 the link 58 with a roller or pin 65 located and positively movedin a groove 8i in the face of a cam or cylinder 52, that is, Isubstitute for the follower 21 in Figs. l to V3 the groove 6l of the cam62 in Fig. 4. The cylinder S2 is fastened to a rotatable shaft and hason its cylindrical surface a groove 63. A roller 511 carried by thebearing projects into the groove 63 of the cylinder 62. With thisarrangement, rotative movement of the disk S2 causes axial movement ofthe bearing, disengagement between roller 5l and cam 52, and engagementof roller 5I with a cam 65 located adjacent cam 52. The center lines ofthe links 51 and 58 in the operative position of roller 5l, that is, inthe position in which the roller engages one of the cams, are designatedby I and in the intermediate position, that is, the position reached atthe end of the first part of the link and cylinder motion is designatedby II. The cylinder 62 represents a positive action cam, more specicallya face cam with regard to the action of groove 6| and a cylindrical camwith regard to the action of groove 63 or with respect to the actions ofboth grooves the cam forms a combined 5 face and cylindrical cam.

With my invention I have accomplished an improved construction andarrangement for a reversing mechanism particularly suited for reversibleinternal combustion engines. 'I'he re- 10 versing operation is effectedby the actuation of a power agency and means which link the sidewisemovement of the roller with the axial movement of the cams so that itcannot happen that for instance the cams are moved axially before theroller has been moved a suflicient distance away from the cam shaft. Itrequires no skill to reverse a combustion engine provided with mymechanism.

Having described the method of op-eration of my invention, together withthe apparatus which I now consider to represent the best embodimentthereof, I desire 4to have it understood that the apparatus shown isonly illustrative and that the invention may be carried out by othermeans.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

l. In a reversible internal combustion engine, the combination of acylinder, provided with a cylinder head, a cam shaft, two cams on theshaft, a slidable bearing having a casing supporting the shaft, a valveactuating means including a push rod and a roller engaging one of thecams, and means disposed substantially below the cylinder head forreversing the engine comprising a single positive action cam having aportion engaging the casing of the bearing, a` rotatable straight shaftmember mounted on the side of said cylinder below said cylinder head andprovided with a pair of arms, a link pivotal- 40 ly connected at one endto one of said arms and at the other end to said push rod, and a secondlink pivoted at one end to the second of said 'arms and at the other endto the positive action cam whereby movement of the positive action cameffects axial movement of the bearing with the cam shaft andsimultaneously removing of the roller from one cam and returning of theroller into engagement with the other cam.

2. In a reversible internal combustion engine, the combination of acylinder having a head, a cam shaft, a bearing supporting the shaft andhaving a casing with two projections, means preventing relative axialmovement between the bearing and the shaft, a support for the bearingpermitting sliding movement of the latter, two cams on the shaft, a pushrod having a roller at its lower end engaging one of the cams, and meansfor reversing the engine comprising a positive action cam extendingbetween the projections on the bearing casing, a link mechanism pivotedat one end to the positive action cam and at the other end to the pushrod and means including a hydraulic motor and a gear connected to thepositive action cam and operated by the motor to cause axial movement ofthe bearing with the shaft and simultaneously removing the roller fromone cam and engaging it with the other cam, the reversing means beingdisposed at the side of said cylinder and below the cylinder head topermit easy removal of the cylinder head Without necessitatingdisassembly of the reversing mechanism.

ALFRED RENNER.

